1. Technical Field of the Invention
The present invention relates to an interface apparatus connecting analog musical instruments such as an electric guitar and an electric base guitar with audio-visual equipments such as a personal computer and a stereo unit. More particularly, the present invention relates to such a digital interface apparatus for analog musical instruments that converts an analog audio signal generated by the analog musical instrument into a digital audio signal, and outputs the digital audio signal to an AV equipment. The present invention also relates to an analog musical instrument equipped with that digital interface.
2. Prior Art
Normally, a so-called electric musical instrument such as an electric guitar and an electric base guitar is a standalone and isolated device, and outputs only an analog audio signal, i.e., an analog electric signal generated by playing the electric musical instrument. The electric musical instrument converts vibration of a string or the like into an analog electric signal, amplifies the analog electric signal with an amplifier or the like, and generates instrumental sounds. The electric musical instruments include an electric guitar, an electric base guitar, and the like of solid type (having no hollow in the body) designed to generate instrumental sounds electrically. By contrast, an acoustic musical instrument generates instrumental sounds through vibration of a string and the like without using an analog electric signal. The acoustic musical instruments include a classic guitar, a wood base, a violin, a cello, and the like. These natural instruments generate sounds acoustically and amplify it through the use of a hollow or the like in the instrument body. The electric musical instruments are considered to include an acoustic musical instrument that has a piezo-electric element and the like capable of converting the generated vibration into an analog electric signal.
As mentioned above, the electric musical instrument outputs only analog audio signals. In fact, it is difficult that another equipment such as an AV equipment controls the electric musical instrument, and vice versa. It has been difficult to provide bidirectional control between the electric musical instruments and the external AV equipments. Generally, the electric musical instrument cannot control other AV equipments. To play music, for example, an output analog audio signal is input to a dedicated peripheral device such as a pre-amplifier and a power amplifier where the signal is adjusted to a specified timbre and is amplified to a specified volume. Finally, the signal is output from an output device such as a speaker. During this musical performance, for example, a tone change may be added to the analog audio signal output from the electric musical instrument. In this case, it is a general practice to control the tone by providing an additional effector device and the like between the electric musical instrument and the pre-amplifier or between the pre-amplifier and the power amplifier.
Since the electric musical instrument outputs an analog audio signal, an additional digital device is required to digitize analog audio signals in order to process these signals by a digital effector, for example. Likewise, an additional converter or the like is required for a digital musical instrument such as a personal computer to process analog audio signals output from the electric musical instrument. The use of the electric musical instrument in a digital environment requires addition of digital devices other than the electric musical instrument, thereby causing a problem of increasing hardware costs. If a digital device and the like are added, these devices are controlled by operating an additional operation system. For example, it is difficult for a player of the electric musical instrument to change or adjust tones at hand. If the electric musical instrument is connected to a digital device such as a computer, it is possible to provide control at least from the electric musical instrument to the digital device. This enables, for example, to edit an output musical sound and the like at hand, making it possible to improve convenience for players.